1. Field of the Invention
This invention relates to an exhaust system including protective arrangements used with combat vehicles and more particularly to such an exhaust system incorporating both ballistic protection and cooling for minimizing the infrared (IR) signature of such vehicles.
2. Description of the Prior Art
Combat vehicles, such as tanks, require a suitable motive power plant for propelling the vehicle over terrain encountered in warfare. Some vehicles in present day use are powered by gas turbine engines which operate at very high temperatures, and the exhaust therefrom, therefore, is also at a very high temperature. Since an exhaust system must necessarily be provided for discharging the gases from the engine to the atmosphere, this exhaust system constitutes a potentially vulnerable area in the vehicle which must be heavily armored.
The exhaust area provides a potential entry area for a shell or missile or other destructive weapon projectiles fired or thrown at the combat vehicle. If the vehicle is to effectively serve its purpose, protection must be provided against the passage of such projectiles through the exhaust area to vital elements internally of the combat vehicle.
One element of such protection for the vehicle is suitable ballistic protection, that is protection against penetration by a shell or missile or other weapon projectile. Secondly, particularly because the gas turbines employed operate, as indicated above, at very high temperatures it is necessary to provide for a reduction of temperature of components in the exhaust area and exhaust gases so as to reduce what is generally referred to as the infrared (IR) signature, that is in an area of high temperature, which can be sensed by various types of IR detectors and IR seeking weapons used against such combat vehicles. For example, heat-seeking missiles can sense the high temperature of the exhaust area and "lock" onto this area so that the missile is guided directly to the exhaust system and potentially into vulnerable vital areas of the combat vehicle with resultant damage thereto.
The prior art discloses combat vehicles which are provided with ballistic protection in the form of armor plate to protect a vital area of a vehicle, for example a radiator. Such armor plate may be in a form of inclined panels of suitable material which provide a shield for the vulnerable part and still permit ingress of cooling air.
The prior art also discloses a variety of arrangements for providing infrared radiation suppression, that is various arrangements for cooling the externally visible surfaces and exhaust gases so as to reduce the temperature thereof and thereby reduce the IR signature. These include arrangements for cooling externally visible surfaces and arrangements for positioning cooler components so as to block an external line of sight to hotter components inwardly thereof.
The present invention, however provides in a very compact form an arrangement which both provides protection against ballistic damage to the vehicle and materially reduces the temperature of the elements of the exhaust system and exhaust gases visible from the exterior of the vehicle so as to reduce the IR signature and thereby minimize the risk of detection or damage to the vehicle by heat-seeking missiles or similar devices.
Accordingly, it is an object of this invention to provide an exhaust system including an integrated protective arrangement which both provides ballistic protection and also reduces IR signature so as to minimize detection or vulnerability to heat-seeking weapons.
It is another object of this invention to reduce the temperature both of surfaces which are directly visible externally of the vehicle and also of surfaces which are not in direct line of sight externally of the vehicle but which nevertheless could provide reflected heat serving as an IR signature.